/*
*    Qizx/open 3.0 beta
*
* This code is the open-source version of Qizx.
* Copyright (C) 2004-2009 Axyana Software -- All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License 
*  Version 1.1 (the "License"); you may not use this file except in 
*  compliance with the License. You may obtain a copy of the License at
*  http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
*  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
*  for the specific language governing rights and limitations under the
*  License.
*
* The Initial Developer of the Original Code is Xavier Franc - Axyana Software.
*
*/
using System;
using QName = System.Qizx.Api.QName;
using ComparisonContext = System.Qizx.XQuery.ComparisonContext;
using ModuleContext = System.Qizx.XQuery.ModuleContext;
namespace System.Qizx.XQuery.Op
{
	
	/// <summary> Variable used as a key in group-by. Can be associated with a collation.</summary>
	public class GroupingVariable:VarReference.Local, ComparisonContext
	{
		virtual public int ImplicitTimezone
		{
			get
			{
				return 0;
			}
			
		}
		public string collation;
		public System.Globalization.CompareInfo collator;
		
		public GroupingVariable(QName name, string collation):base(name)
		{
			this.collation = collation;
		}
		
		public override Expression StaticCheck(ModuleContext context, int flags)
		{
			decl = context.lookforLocalVariable(name);
			if (decl == null)
			// cannot be a global: (not specified, but woulnt make sense)
				context.error("XQST0094", this, "grouping variable " + context.PrefixedName(name) + " not declared (must be local)");
			else
			{
				type = decl.type;
				decl.use();
			}
			if (collation != null)
			{
				collator = context.getCollator(collation);
				if (collator == null && collation != null)
					context.error("XQST0076", this, "unknown collation " + collation);
			}
			return this;
		}
		
		public virtual System.Globalization.CompareInfo getCollator()
		{
			return collator;
		}
		
		public virtual bool emptyGreatest()
		{
			return false;
		}
	}
}